Method to re-synchronize live media streams, commands, and on-screen events transmitted through different internet pathways

ABSTRACT

Systems maintain synchronicity among elements intended to be displayed at various points during a live media stream. At a multimedia player, start playback of a live media stream. The systems receive input from a user selecting a new time of the media stream to playback, which is different than the current playback time of the media stream. The systems adjust playback of the media stream to restart at the new selected time, such that the current playback time of the output media stream is updated to the new selected time. The systems monitor the current playback time of the media stream as adjusted. The systems determine a user-initiated command to execute for displaying one or more visual elements at the multimedia player by polling a command manifest file based on the current playback time as adjusted.

RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.16/785,310, filed Feb. 7, 2020, which is a continuation of U.S.application Ser. No. 15/922,297, filed Mar. 15, 2018, now U.S. Pat. No.10,560,502, issued on Feb. 11, 2020, which claims the benefit of U.S.Provisional Application No. 62/549,620, filed on Aug. 24, 2017. Thisapplication is related to U.S. application Ser. No. 15/922,557, filedMar. 15, 2018, which is incorporated by reference in its entirety. Theentire teachings of the above applications are incorporated herein byreference.

BACKGROUND

As network bandwidth has increased over the years, multimedia technologyhas made it possible to broadcast multimedia programs and contentcomprising multiple corresponding media streams, such as a webcast, overthe Internet to user devices for viewing. Multimedia technology hasfurther enabled transmitting each of the media streams from differentsources through different Internet pathways to the user devices. Forexample, the multimedia content may be an online video presentation,comprised of a live video image of a presenter streamed over an Internetpathway to viewer/player devices. The content may also comprise acorresponding sequence of presentation slides being discussed by thespeaker, which is streamed from a separate device over a separatenetwork pathway to the user devices. However, due to differinglatencies, encoding and transcoding times, network and local buffering,and other such delays in the different Internet pathways, the receipt ofthe media stream and the presentation slides through different pathwaysare typically out of synchronization when they arrive at a viewingdevice. For example, the playback of the streamed live video over thefirst network pathway may be received seconds or even minutes behind thesequence of presentation slides received over the other network pathway.Such time discrepancies between receipt of the corresponding mediastreams may also vary among the different user devices receiving themedia streams. Because the streamed media and the on-screen events thatare intended to be viewed in synchronization with the streamed media mayarrive at the viewer's computer at different times because of thesevarying and unpredictable delays, combining them into a unified viewingexperience without re-synchronization risks an incoherent viewingexperience.

SUMMARY

Embodiments of the present invention are directed to computer systems,methods, and program products for re-synchronizing different mediastreams of multimedia content, commands, and on-screen events that aretransmitted over different Internet pathways using multimedia streamingtechnology.

Some computer system embodiments re-synchronize the playback of a livemedia stream with the execution of a stream of out-of-band commands. Inthese computer system embodiments, the system may comprise a mediaencoder operated by a publisher user. In some embodiments, the mediaencoder is implemented as one of a software-based media encoder, ahardware-based media encoder, or a cloud-based media encoder. In exampleembodiments, the media encoder is one of: Telstra Wirecast, Adobe LiveMedia Encoder, NewTek TriCaster, Zoom Video Webinar, Pexip Infinity, orsuch. The media encoder is configured to capture input from sourcedevices. In some embodiments, the input is at least one of video andaudio, and the source devices are at least one of: camera or microphone.The media encoder is configured to encode the captured input to astandard media format, such as MPEG-4, H.264, and the like. The mediaencoder is configured to transmit the encoded input as a stream, using areal-time streaming protocol, to a streaming media server. The real-timestreaming protocol may be one of: Real-Time Messaging Protocol (RTMP),Real-Time Streaming Protocol (RTSP), Web Real-Time Communications(WebRTC), and such.

In computer system embodiments, the system may further comprise thestreaming media server coupled to the media encoder. In someembodiments, the streaming media server is one of: Wowza StreamingEngine, Adobe Media Server, or a cloud-hosted SaaS/PaaS provider,including one of: Brightcove Live Streaming Service, Zencoder LiveTranscoding, Encoding.com Live Cloud Encoding, AWS Elemental MediaLive,Wowza Streaming Cloud, or such. The streaming media server is configuredto receive the input media stream from the media encoder. The streamingmedia server is configured to transcode the received input media streamto a live streaming format compatible with content delivery (referred toas an output media stream). In some embodiments, the media stream istranscoded by the streaming media server using a Hypertext TransferProtocol (HTTP) protocol that is one of: HTTP Live Streaming (HLS),MPEG-DASH, or such. The streaming media server is configured to generateand maintain a media stream playlist. In some embodiments, the generatedmedia stream playlist maintains references to older media segments ofthe transcoded media stream, while gaining references to new mediasegments, throughout full duration of the input media stream. Thestreaming media server is configured to at least one of: host the outputmedia stream or transmit the output media stream to a ContentDistribution Network (CDN) for delivery.

In computer system embodiments, the system comprises a publishing clientlogically independent of the media encoder and streaming media server.The publishing client is operated by the publisher user simultaneous tooperation of the media encoder by the publisher user. The publishingclient is configured to prompt the publisher user to enter location ofthe output media stream and prompt the publisher user to enter starttime at which the media encoder began encoding the input media stream.The publishing client is also configured to enable the publisher user toadjust an offset time and enable the publisher user to initiate commandsat particular times. The user-initiated commands are relevant to theinput being simultaneously captured by the media encoder. In someembodiments, the user-initiated commands include at least one of acommand to display a slide image, a notification message, anadvertisement, a statistic, a sporting event score, a caption, atranslation, a video overlay, a question, a social media post, a chat ortext message, a survey, a live web page, a footnote, a thumbnail, achapter title, and such. The publishing client is configured to transmitthe location of the output media stream, the start time of the inputmedia stream, the adjusted offset time, and the user-initiated commandsto a publishing server.

In computer system embodiments, the system further comprises thepublishing server coupled to the publishing client. The publishingserver is configured to receive the location of the output media stream,the start time of the input media stream, the adjusted offset time, andthe user-initiated commands from the publishing client. The publishingserver is also configured to generate and maintain a command manifestfile. In some embodiments, the command manifest file is in a text formatthat is one of: CSV, JSON, or XML. The publishing server is configuredto write the location of the output media stream and the start time ofthe input media stream as a command (e.g., first command) in the commandmanifest file. The publishing server is further configured to append thesequence of the user-initiated commands to the command manifest file asthe user-initiated commands are received from the publishing client.Each new command is appended to the end of the command manifest filetogether with a clock time in which the new command is received by thepublishing server and the adjusted offset time. In some embodiments,each new command is appended to the end of the command manifest file asone of: a new line of text or a data object. The publishing server isconfigured to at least one of: host the command manifest file ortransmit the command manifest file to a CDN for delivery.

In computer system embodiments, the system further comprises amultimedia player running on a client device of a viewer user. In someembodiments, the multimedia player runs in one of: a web browser, amobile application, or such on the client device. The multimedia playeris configured to retrieve the command manifest file from at least oneof: the publishing server or the CDN. The multimedia player isconfigured to parse the location of the output media stream from theretrieved command manifest file and load, buffer, and present the outputmedia stream to the viewer user. The multimedia player is furtherconfigured to poll for user-initiated commands appended to the commandmanifest file and start playback of the output media stream.

The multimedia player is then configured to monitor current playbacktime of the output media stream. In some embodiments, the currentplayback time is calculated as number of milliseconds between the starttime of the input media stream and time of a currently presented frameof the output media stream. The multimedia player is configured todetermine whether to execute a command of the command manifest file in auser interface of the multimedia player based on the current playbacktime. In some embodiments, if the sum of the media start time and thecurrent playback time is (a) greater than or equal to the sum of servertime that a particular command was received, plus the offset time of theparticular command, and (b) less than the sum of server time that a nextcommand in the sequence of user-initiated commands was received, plusoffset time of the next command, the multimedia player is configured toexecute the command in the user interface of multimedia player. Inexample embodiments, executing the command includes one of: displaying aslide image or a notification message to the viewer user displaying aslide image, a notification message, an advertisement, a statistic, asporting event score, a caption, a translation, a video overlay, aquestion, a social media post, a chat or text message, a survey, a liveweb page, a footnote, a thumbnail, a chapter title, and such. Further,if the output media stream is paused or rewound, when the multimediaplayer restarts the paused or rewound output media stream at arespective playback time, the multimedia player is configured todetermine whether to execute a command of the polled user-initiatedcommands in a user interface of the multimedia player based on therespective playback time.

In other computer system embodiments, the system comprises a mediaencoder configured to capture a continuous live media stream of online(e.g., web-based) multimedia content transmitted through a first networkpathway (e.g., over an out-of-band network). The live media stream maycontain at least one of: live or pre-recorded video, audio, oranimation. The system further comprises a streaming media server coupledto the media encoder through the first network pathway. The streamingmedia server is configured to generate and maintain an output mediastream playlist such that the playlist maintains all references to oldermedia segments while gaining new references, throughout the fullduration of the stream. The streaming media server transcodes the livemedia stream into segments or packets of a target time length, which arestored at a dedicated memory location. The streaming media server alsocreates and updates a metadata file or structure (i.e., playlist file),such as in a text, XML, JSON, or CSV file, with information on thesequence of segments or packets of the live media stream. Theinformation stored in the playlist file includes information on eachstored segment of the live media stream, such as where stored, hosted,identifier, date, time, size (time length), and the like.

In example other system embodiments, the media encoder is a videoclient, the streaming media server is a video server, and the live mediastream is a video stream. In these embodiments, the media encoder isconfigured to capture the live video stream as one of: MPEG-4, WindowsMedia, Quicktime, Audio Video Interleave (AVI), and the like. In theseembodiments, the video stream may be at least one of transcoded andtransmitted over the network using HTTP Live Streaming (HLS) protocol,MPEG-DASH protocol, or other such streaming protocol.

In the other computer system embodiments, the system further comprises apublishing client which may be communicatively coupled to the mediaencoder. The publishing client is configured to catalog, store, andtransmit media content, such as images, text, and interactive elements,that are intended to be viewed in synchronization with the live mediastream. The publishing client is further configured to create a streamof commands, each of which might be associated with an on-screen eventthat is intended to be displayed on a viewing device at a specificmoment as the live media stream is being player on that viewing device.The publishing server generates and maintains a command manifest(metadata) file to record triggered on-screen events of the commandstream. In example embodiments, the command file is a manifest filestructured in text, XML, JSON, CSV, or the like. The publishing serveris configured to record each triggered event in the command manifestfile with an associated event time computed based on the start time ofthe live media stream. In example embodiments, the command stream is aset of slides and the sequence of events is a sequence of changing theslide during the online presentation.

In some of the other system embodiments, the publishing server isconfigured to generate the command manifest file in communication withthe publishing client. As a new event of the sequence of events istriggered (e.g., by a user), the publishing client is configured tocapture the new triggered event and transmit a notification of the newtriggered event to the publishing server. The publishing server isconfigured to set the start time of the live media stream and determinethe offset between the start time of the sequence of events and the setstart time of the live media stream. The publishing server is furtherconfigured to determine the clock time for the new triggered event. Thepublishing server is configured to compute an event time for the newtriggered event based on the determined clock time and the determinedoffset. The publishing server is configured to then record (log) anidentifier of the new triggered event and the computed event time in thecommand file.

In the other computer system embodiments, the system further comprises amultimedia player coupled to the streaming media server and thepublishing server through two different internet pathways. Each of thesepathways may experience different encoding and transmission delays orlatencies, so that the live media stream and the command stream mayarrive many seconds or even minutes out of synchronization, due to thesedifferent latencies. The multimedia player is configured to present thelive media stream retrieved from the streaming media server. Themultimedia player is further configured to poll the playlist at thestreaming media server to determine a current playback time of the livemedia stream based on the start time of the live media stream. In someembodiments, the multimedia player is configured to retrieve the currentmedia playback time from the embedded media player. The multimediaplayer is also configured to poll the command file at the publishingserver to determine a new triggered event and associated event time. Ifthe event time of the new triggered event corresponds to the currentplayback time of the live media stream, the multimedia player isconfigured to present the new event on the multimedia playersynchronized (locked) to the live media stream. In example embodiments,the multimedia player is configured with an embedded browser-based mediaplayer.

Some computer-implemented method embodiments re-synchronize the playbackof a live media stream with the execution of a stream of out-of-bandcommands. In these computer-implemented method embodiments, the methodperforms operations at a media encoder operated by a publisher user. Insome embodiments, the media encoder is implemented as one of asoftware-based media encoder, a hardware-based media encoder, or acloud-based media encoder. In example embodiments, the media encoder isone of: Telstra Wirecast, Adobe Live Media Encoder, NewTek TriCaster,Zoom Video Webinar, Pexip Infinity, or such. The method, at the mediaencoder, captures input from source devices. In some embodiments, theinput is at least one of video and audio, and the source devices are atleast one of: camera or microphone. The method, at the media encoder,encodes the captured input to a standard media format, such as MPEG-4,H.264, and the like. The method, at the media encoder, transmits theencoded input as a stream, using a real-time streaming protocol, to astreaming media server. The real-time streaming protocol may be one of:Real-Time Messaging Protocol (RTMP), Real-Time Streaming Protocol(RTSP), Web Real-Time Communications (WebRTC), and such.

In computer-implemented method embodiments, the method performsoperations at the streaming media server coupled to the media encoder.In some embodiments, the streaming media server is one of: WowzaStreaming Engine, Adobe Media Server, or a cloud-hosted SaaS/PaaSprovider, including one of: Brightcove Live Streaming Service, ZencoderLive Transcoding, Encoding.com Live Cloud Encoding, AWS ElementalMediaLive, Wowza Streaming Cloud, or such. The method, at the streamingmedia server, receives the input media stream from the media encoder.The method, at the streaming media server, transcodes the received inputmedia stream to a live streaming format compatible with content delivery(referred to as an output media stream). In some embodiments, the mediastream is transcoded by the streaming media server using a HypertextTransfer Protocol (HTTP) protocol that is one of: HTTP Live Streaming(HLS), MPEG-DASH, or such. The method, at the streaming media server,generates and maintains a media stream playlist. In some embodiments,the generated media stream playlist maintains references to older mediasegments of the transcoded media stream, while gaining references to newmedia segments, throughout full duration of the input media stream. Themethod, at the streaming media server, at least one of: hosts the outputmedia stream or transmits the output media stream to a ContentDistribution Network (CDN) for delivery.

In computer-implemented method embodiments, the method performsoperations at a publishing client logically independent of the mediaencoder and streaming media server. The publishing client is operated bythe publisher user simultaneous to operation of the media encoder by thepublisher user. The method, at the publishing client, prompts thepublisher user to enter location of the output media stream and promptsthe publisher user to enter start time at which the media encoder beganencoding the input media stream. The method, at the publishing client,also enables the publisher user to adjust an offset time and enables thepublisher user to initiate commands at particular times. Theuser-initiated commands are relevant to the input being simultaneouslycaptured by the media encoder. In some embodiments, the user-initiatedcommands include at least one of: a slide image, a notification message,an advertisement, a statistic, a sporting event score, a caption, atranslation, a video overlay, a question, a social media post, a chat ortext message, a survey, a live web page, a footnote, a thumbnail, achapter title, or such. The method, at the publishing client, transmitsthe location of the output media stream, the start time of the inputmedia stream, the adjusted offset time, and the user-initiated commandsto a publishing server.

In computer-implemented method embodiments, the method performsoperations at the publishing server coupled to the publishing client.The method, at the publishing server, receives the location of theoutput media stream, the start time of the input media stream, theadjusted offset time, and the user-initiated commands from thepublishing client. The method, at the publishing server, also generatesand maintains a command manifest file. In some embodiments, the commandmanifest file is in a text format that is one of: CSV, JSON, or XML. Thepublishing server is configured to write the location of the outputmedia stream and the start time of the input media stream as a firstcommand in the command manifest file. The method, at the publishingserver, appends the sequence of the user-initiated commands to thecommand manifest file as the user-initiated commands are received fromthe publishing client. Each new command is appended to the end of thecommand manifest file together with a clock time in which the newcommand is received by the publishing server and the adjusted offsettime. In some embodiments, each new command is appended to the end ofthe command manifest file as one of: a new line of text or a dataobject. The method, at the publishing server, at least one of: hosts thecommand manifest file or transmits the command manifest file to a CDNfor delivery.

In computer-implemented method embodiments, the method performsoperations at a multimedia player running on a client device of a vieweruser. In some embodiments, the multimedia player runs in one of: a webbrowser, a mobile application, or such on the client device. The method,at the multimedia player, retrieves the command manifest file from atleast one of: the publishing server or the CDN. The method, at themultimedia player, retrieves the command manifest file from at least oneof: the publishing server or the CDN. The method, at the multimediaplayer, parses the location of the output media stream from theretrieved command manifest file and loads, buffers, and presents theoutput media stream to the viewer user. The method, at the multimediaplayer, polls for user-initiated commands appended to the commandmanifest file and starts playback of the output media stream.

The method, at the multimedia player, then monitors current playbacktime of the output media stream. In some embodiments, the currentplayback time is calculated as number of milliseconds between the starttime of the input media stream and time of a currently presented frameof the output media stream. The method, at the multimedia player,determines whether to execute a command of the command manifest file ina user interface of the multimedia player based on the current playbacktime. In some embodiments, if the sum of the media start time and thecurrent playback time is (a) greater than or equal to the sum of servertime that a particular command was received, plus the offset time of theparticular command, and (b) less than the sum of server time that a nextcommand in the sequence of user-initiated commands was received, plusoffset time of the next command, execute the command in the userinterface of multimedia player, the method executes the command in theuser interface of the multimedia player. In example embodiments,executing the command includes one of: displaying a slide image or anotification message to the viewer user displaying a slide image, anotification message, an advertisement, a statistic, a sporting eventscore, a caption, a translation, a video overlay, a question, a socialmedia post, a chat or text message, a survey, a live web page, afootnote, a thumbnail, and a chapter title, or such. Further, if theoutput media stream is paused or rewound, when restarting the paused orrewound output media stream at a respective playback time, determiningwhether to execute a command of the polled user-initiated commands in auser interface of the multimedia player based on the respective playbacktime.

In other computer-implemented method embodiments, the method initiates alive media stream of an online presentation transmitted through a firstnetwork pathway over an out-of-band network. The method also stores thestart time corresponding to the initiation of the live media stream. Asthe live media stream is being continuously streamed over the network(via the first network pathway), the method presents the live mediastream on a multimedia player. The method also polls a metadata file(i.e., playlist file) configured on a streaming media server todetermine a current playback time of the live media stream based on thestored start time. In example embodiments, the playlist is a manifestfile structured in XML, JSON, CSV, text, or the like.

In example other method embodiments, the live media stream is a livevideo stream. In these other embodiments, the method captures the videostream as one of: MPEG-4, Windows Media, Quicktime, Audio VideoInterleave (AVI), and the like. In these other embodiments, the videostream may be at least one of transcoded and transmitted over thenetwork using HTTP Live Streaming (HLS) protocol, MPEG-DASH protocol, oranother streaming protocol. In example embodiments, the multimediaplayer is configured with a browser-based video player and the metadatafile (e.g., playlist file) is structured as a manifest that listsInternet locations where each segment of the live media stream islocated for retrieval and playback. This manifest is read by thebrowser-based video player, which plays back the live media streamsegments in the proper order, and determines the current media playbacktime of the live media stream.

In these other computer-implemented method embodiments, the method alsopolls a command file to determine a new triggered event of a sequence ofevents logged to the file. In example embodiments, the command file is amanifest file in text, XML, JSON, CSV, or the like. The sequence ofevents is associated with a command stream of the online presentationtransmitted over a second network pathway. In example other methodembodiments, the command stream is a set of slides and the sequence ofevents is a sequence of changing the slide during the onlinepresentation. The new triggered event has an associated event timecomputed based on the stored start time of the live media stream. If theevent time of the new triggered event corresponds to the currentplayback time of the live media stream, the method presents the newtriggered event on the multimedia player synchronized (locked) to thelive media stream.

In these other method embodiments, the method generates and logs to thecommand file as follows. As a new event of the sequence of eventstriggers (e.g., by a user), the method captures the new triggered event.The method determines clock time for the new triggered event. The methodalso determines the offset between the stored start time of the livemedia stream and start time of the sequence of events. The methodcomputes an event time for the new triggered event based on thedetermined clock time and the determined offset. The method records(logs) an identifier of the new triggered event and the computed eventtime in the command file synchronized (locked) to the live media stream.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing will be apparent from the following more particulardescription of example embodiments, as illustrated in the accompanyingdrawings in which like reference characters refer to the same partsthroughout the different views. The drawings are not necessarily toscale, emphasis instead being placed upon illustrating embodiments.

FIG. 1A is a schematic diagram of an example computer networkenvironment in which embodiments of the present invention are deployed.

FIG. 1B is a block diagram of the computer nodes in the network of FIG.1A.

FIG. 2A is a block diagram of a system for re-synchronizing playback ofa live media stream with a stream of commands and on-screen eventsaccording to embodiments of the present invention.

FIG. 2B is a screenshot of an example multimedia player withsimultaneous playback of a live media stream with the display of slideimages in an example embodiment of the present invention.

FIG. 2C is a screenshot of an example user interface for entering offsettime at a publishing client in an example embodiment of the presentinvention.

FIG. 2D is a screenshot of an example user interface for entering thelocation of a live media stream at a publishing client in an exampleembodiment of the present invention.

FIG. 2E is a screenshot of an example user interface for where commandsare issued to change the selected slides at a publishing client in anexample embodiment of the present invention.

FIGS. 2F and 2G are example command manifest data files generated inexample embodiments of the present invention.

FIG. 3A is a block diagram of computer components of a multimedia playerin embodiments of the present invention.

FIG. 3B is a block diagram of computer components of a publishing clientin embodiments of the present invention.

FIG. 3C is a block diagram of computer components of a publishing serverin embodiments of the present invention.

FIG. 4 is a flowchart of an example method of re-synchronizing playbackof a live media stream with a stream of commands and on-screen eventsaccording to embodiments of the present invention.

FIG. 5A is a sequence diagram of the timeline of re-synchronizing theplayback of a live media stream to a stream of commands and on-screenevents in embodiments of the present invention.

FIG. 5B is another sequence diagram of the timeline of re-synchronizinga stream of commands to a selected playback time of a live media streamin embodiments of the present invention.

DETAILED DESCRIPTION

A description of example embodiments follows.

The teachings of all patents, published applications and referencescited herein are incorporated by reference in their entirety.

Digital Processing Environment

Example implementations of a multimedia system 100 for re-synchronizinga current playback time of a live media stream with execution of astream of out-of-band commands and on-screen events in an online (e.g.,web-based) presentation may be implemented in a software, firmware, orhardware environment. FIG. 1A illustrates one such environment. Clientcomputer(s)/devices 150 (e.g. a mobile phone) and a cloud 160 (or servercomputer or cluster thereof) provide processing, storage, andinput/output devices executing application programs and the like.

Client computer(s)/devices 150 are be linked through communicationsnetwork 170 to other computing devices, including other clientdevices/processes 150 and server computer(s) 160. Communications network170 can be part of a remote access network, a global network (e.g., theInternet), an out-of-band network, a worldwide collection of computers,Local area or Wide area networks, cloud networks, and gateways thatcurrently use respective protocols (TCP/IP, HTTP, Bluetooth, etc.) tocommunicate with one another. Other electronic device/computer networkarchitectures are suitable.

Sever computers 160 may be configured to implement a streaming mediaserver (e.g., 215 of FIG. 2A) for provisioning, formatting, and storingthe live media stream (such as audio, video, text, and images/pictures)of a presentation, which are processed and played at clientcomputer(s)/devices 150 (such as multimedia players 232-238 in FIG. 2A).The server computers 160 are communicatively coupled to clientcomputer(s)/devices 150 that implement respective media encoders (e.g.,210 of FIG. 2A) for capturing, encoding loading, or otherwise providingthe live media stream that are transmitted to the server computers 160.In one example embodiment, one or more of the server computers 160 areJava application servers that are scalable such that if there are spikesin traffic, the servers can handle the load increase.

A first server computer 160 (e.g., streaming media server 215 of FIG.2A) may receive and partition a live media stream captured/recorded atan associate first client computer/device 150 (e.g., media encoder 210of FIG. 2A) into segments. The first server computer 160 may storeinformation related to the segments in a metadata structure. A secondclient computer/device 150 (e.g., publishing client 220 of FIG. 2A) maydetect a user-initiated command of a stream of user-initiated commandsdetected by the second client computer/device 150. The second clientcomputer/device 150 may register the user-initiated command (e.g.,sequencing or selecting a new slide, displaying a slide image, anotification message, an advertisement, a statistic, a sporting eventscore, a caption, a translation, a video overlay, a question, a socialmedia post, a chat or text message, a survey, a live web page, afootnote, a thumbnail, a chapter title, and such) and notify the secondserver computer 160 (e.g., publishing server 225 of FIG. 2A) of theuser-initiated command and an associated start time of the live mediastream, offset time, and location of the live media stream. The secondserver computer 160 may record (e.g., in a manifest file as shown inFIGS. 2F and 2G) one or more of: an identifier of the user-initiatedcommand, a command type, a command parameter, server clock time, starttime of the media stream, and parameters of the user-initiated command,and such.

Other client computers/devices 150 (such as multimedia players 232-238in FIG. 2A) may retrieve information from the command manifest file anduse the information to re-synchronizing playback of a live media streamwith execution of the user-initiated command for display in thepresentation. For example, a user (viewer) may select to view the livemedia stream event from any point in the live media stream, and commandsare executed in the intended synchronization with the viewed live mediastream to properly display visual elements associated with the livemedia stream. The user may further interact with displayed visualelements (e.g., chapter title) to cause the live media stream to re-cueto the corresponding point in the live media stream, and re-synchronizeall other displayed visual elements to the re-cued media stream (e.g.,statistics or scores).

FIG. 1B is a diagram of the internal structure of a computer/computingnode (e.g., client processor/device/mobile phone device/tablet 150 orserver computers 160) in the processing environment of FIG. 1A, whichmay be used to facilitate displaying such audio, video, image, or datasignal information. Each computer 150, 160 contains a system bus 110,where a bus is a set of actual or virtual hardware lines used for datatransfer among the components of a computer or processing system. Bus110 is essentially a shared conduit that connects different elements ofa computer system (e.g., processor, disk storage, memory, input/outputports, etc.) that enables the transfer of data between the elements.Attached to system bus 110 is I/O device interface 82 for connectingvarious input and output devices (e.g., keyboard, mouse, touch screeninterface, displays, printers, speakers, etc.) to the computer 150, 160.Network interface 86 allows the computer to connect to various otherdevices attached to a network (for example the network illustrated at170 of FIG. 1A). Memory 114 provides volatile storage for computersoftware instructions 115 and data 116 used to implement a softwareimplementation of the present invention (e.g. capturing/loading,provisioning, formatting, retrieving, downloading, and/or storing livemedia streams and stream of user-initiated commands).

Disk storage 95 provides non-volatile storage for computer softwareinstructions 92 (equivalently “OS program”) and data 94 used toimplement embodiments of the multimedia system 100 of the presentinvention. Central processor unit 84 is also attached to system bus 110and provides for the execution of computer instructions.

In one embodiment, the processor routines 92 and data 94 are a computerprogram product, including a computer readable medium capable of beingstored on a storage device 95, which provides at least a portion of thesoftware instructions for the multimedia system 100. Instances of thetiming selector 1102, timing selector 1132, event time adjuster 1152,synchronizer 1103, event capturer 1133, event recorder 1153, publisher1136, player 1106, search engine 1107 (of FIGS. 3A-3C), and othersoftware embodiments of the multimedia system 100 may be implemented asa computer program product 92, and can be installed by any suitablesoftware installation procedure, as is well known in the art. In anotherembodiment, at least a portion of the multimedia system 100 instructionsmay also be downloaded over a cable, communication and/or wirelessconnection. In other embodiments, the multimedia system 100 softwarecomponents may be implemented as a computer program propagated signalproduct embodied on a propagated signal on a propagation medium (e.g., aradio wave, an infrared wave, a laser wave, a sound wave, or anelectrical wave propagated over a global network such as the Internet,or other network(s)). Such carrier medium or signals provide at least aportion of the software instructions for the multimedia system 100routines/program 92.

In alternate embodiments, the propagated signal is an analog carrierwave or digital signal carried on the propagated medium. For example,the propagated signal may be a digitized signal propagated over a globalnetwork (e.g., the Internet), a telecommunications network, anout-of-band network, or other network. In one embodiment, the propagatedsignal is transmitted over the propagation medium over a period of time,such as the instructions for a software application sent in packets overa network over a period of milliseconds, seconds, minutes, or longer. Inanother embodiment, the computer readable medium of computer programproduct 92 is a propagation medium that the computer system 150 mayreceive and read, such as by receiving the propagation medium andidentifying a propagated signal embodied in the propagation medium, asdescribed above for computer program propagated signal product.

The multimedia system 100 described herein may be configured using anyknown programming language, including any high-level, object-orientedprogramming language. A client computer/device 150 (e.g., multimediaplayer 232, 234, 238 of FIG. 2A) of the multimedia system 100 may beimplemented via a software embodiment and may operate within a browsersession. The multimedia system 100 may be developed using HTML,JavaScript, Flash, and such. The HTML code may be configured to embedthe system into a web browsing session at a client 150. The Java Scriptcan be configured to perform clickstream and session tracking at theclient 150 (e.g., publishing client 220 of FIG. 2A) and store thestreaming media recordings and editing data in a cache. In anotherembodiment, the system may be implemented in HTML5 for client devices150 that do not have Flash installed and use HTTP Live Streaming (HLS)or MPEG-DASH protocol. The system may be implemented to transmit mediastreams using a real-time streaming protocol, such as: Real-TimeMessaging Protocol (RTMP), Real-Time Streaming Protocol (RTSP), WebReal-Time Communications (WebRTC), and the like. Components of themultimedia system 100 may be configured to create and load an XML, JSON,or CSV data file or other structured metadata file (such as a manifestfile) with information about where and how components of the multimediasystem 100 are stored, hosted, or formatted, such as timing information,size, footnote, attachments, interactive components, style sheets, etc.

In an example mobile implementation, the user interface framework forthe components of the multimedia system 100 may be based on XHP, Javelinand WURFL. In another example mobile implementation for OS X and iOSoperating systems and their respective APIs, Cocoa and Cocoa Touch maybe used to implement the player 102 using Objective-C or any otherhigh-level programming language that adds Smalltalk-style messaging tothe C programming language.

System for Re-Synchronizing

FIG. 2A is a block diagram of a system 200 for re-synchronizing theplayback of a live media stream with the execution of a stream ofout-of-band commands and on-screen events in an example embodiment ofthe present invention. These commands typically trigger on-screenevents, such as changes in displayed images, text, and interactiveelements. The system 200 is an example implementation of the computernetwork environment 100 of FIG. 1A. In FIG. 2A, the system 200re-synchronizes the playback of a live media stream with the executionof a stream of commands transmitted through different Internet pathways.The encoding, transmission, transcoding, distribution, download, andbuffering of the live media stream may result in a latency between thetime of capture and the time of playback in the multimedia players 232,234, 238 that is different from the latency between the time a commandwas initiated by a publisher and the time is received by the multimediaplayers. For example, a particular frame of media may be captured at themedia encoder 210 simultaneous to the time that a corresponding commandwas initiated by a publisher at the publishing client 220, but themultimedia players 232, 234, 238 may receive the command in the commandstream before the corresponding frame of media is displayed duringplayback. The difference between the latencies may vary among differentmultimedia player clients 232, 234, 238. In other embodiments, thesystem 200 may re-synchronize any number of media streams and commandstreams through any number of different Internet pathways withoutlimitation. The user may also select a particular point (time) in thelive media stream or interaction with one or more visual elements (oron-screen events) displayed by from the execution one or more commandsof the stream of commands, resulting in the system 200 re-synchronizingthe playback of the live media stream with the stream of commands.

The system 200 includes a media encoder 210 that captures, loads, orotherwise provides the live media stream (containing media content) to astreaming media server 215. In some embodiments, the media encoder 210may be: Telstra Wirecast, Adobe Live Media Encoder, NewTek TriCaster,Zoom Video Webinar, Pexip Infinity, and the like. In some embodiments,the streaming media server 215 may be Wowza Streaming Engine, AdobeMedia Server, or a cloud-hosted SaaS/PaaS provider, including one of:Brightcove Live Streaming Service, Zencoder Live Transcoding,Encoding.com Live Cloud Encoding, AWS Elemental MediaLive, WowzaStreaming Cloud, or such. The media content of the live media stream maybe audio and/or video, and the like. In example embodiments, the livemedia stream may contain video content, which is being captured live (inreal-time) from a camera/recorder (e.g., webcam) configured on the mediaencoder 210, a camera/recorder communicatively coupled to the mediaencoder 210, or any other such live capture of video. In otherembodiments, the video content of the live media steam may bepre-recorded videos stored on the media encoder 210 or at a storagedevice communicatively coupled to the media encoder 210, a live videofeed from a web link accessible from the media encoder 210, and such.

In example embodiments, the captured video content of the video streammay be formatted as MPEG-4, Windows Media, Quicktime, Audio VideoInterleave (AVI), Flash, or any other video format without limitation.In some example embodiments, the video stream may also be transcoded(video encoded) or otherwise digitally converted for transfer and use atthe streaming media server 215 and multimedia players 232, 234, 238. Thevideo stream (or other media stream) may be transferred to the streamingmedia server 215 and multimedia players 232, 234, 238 using Real-TimeMessaging Protocol (RTMP) or HTTP Live Streaming (HLS) or other suchstreaming protocol.

The streaming media server 215 receives the (continuous) live mediastream from the media encoder 210 over network 340. The streaming mediaserver 215 is configured to generate and maintain an output media streamplaylist such that the playlist maintains all references to older mediasegments while gaining new references, throughout the full duration ofthe stream (e.g., 2 hours). The streaming media server 215 provides adedicated memory location (e.g., directory or folder) for storing thelive media stream. The streaming media server 215 provisions thereceived live media stream for playback on multimedia players 232, 234,236. The streaming media server 215 transcodes the live media streaminto segments or packets of a target time length, which are stored atthe dedicated memory location. The streaming media server 215 alsocreates and updates a metadata file or structure (e.g. playlist file),such as in a text, XML, or CSV file, with information on the sequence ofsegments or packets of the live media stream. The information stored inthe playlist file includes information on each stored segment of thelive media stream, such as where stored, hosted, identifier, date, time,size (time length), and the like. The stored segments and playlist filemay be structured according to the player configuration of themultimedia players 232, 234, 236, such as in HTML5-capable browserclient.

Based on the playlist file, the multimedia players (i.e., firstmultimedia player 232, second multimedia player 234, through nthmultimedia player 238) retrieve the live (continuous) media stream fromthe streaming media server 215, and may cache the live media stream atthe multimedia players. In embodiments, the live media stream may beretrieved through a first content distribution network (CDN) 218. Themultimedia players 232, 234, 238 display the live media stream viarespective media players (e.g., HTML5 Video Player or the like)configured on the multimedia players 232, 234, 238 via a web browser.The live media stream may be displayed in a first window or panel of amultimedia player 232, 234, 238.

FIG. 2B illustrates an example multimedia player 232, 234, 238displaying a live media stream 272 in a first window or panel as part ofa presentation (e.g., webcast). A user may select to adjust playback ofthe live media stream 272 at any point (time) using a navigationtimeline 275, or pause and review playback 281 using the navigationtimeline 275. In FIG. 2B, the example multimedia player 232, 234, 238also displays a second window with visual elements (or on-screen events)displayed by the execution of one or more commands synchronized to thelive media stream 272. These visual elements include custom branding 271for the presentation, a speaker profile 273 for the speaker of thepresentation, dynamic footnotes and handouts 274 for the presentation,and follow-along topic list and thumbnails 276 for the presentation. Theexample multimedia player of FIG. 2B also displays a third window withanother visual element of animated presentation slides 280 displayed bythe execution of one or more commands synchronized to the live mediastream 272, and a fourth window with visual elements for submitting aquestion 282 by the user related to the current playback point (time) ofthe live media stream 272. Selecting of one of the visual elements(e.g., one of the dynamic footnotes 274) may re-cue the live mediastream 272, and re-synchronize all other displayed visual elements(e.g., topic list and thumbnails 276, animated presentation slides 280,and such) to the playback time of the re-cued live media stream 272. Theexample multimedia player of FIG. 2B also includes option to present thepresentation in a fullscreen 277, control zoom 278, and downloadattachments 279.

The multimedia player 232, 234, 238 may determine the playback time ofthe live media stream. In some embodiments, the playback time may be thenumber of milliseconds between the starting point of the media and thecurrently presented frame. To do so, the multimedia player 232, 234, 238polls the API of the HTML5 Video Player via the web browser. In someembodiments, the current playback time may be stored in memory (cache)at the multimedia player 232, 234, 238.

The system 200 also includes the publishing client 220 that provides astream of user-initiated commands to a publishing server 225. Whenreceived and executed by the multimedia players 232, 234, 238, thecommands trigger on-screen events in the multimedia player userinterface such as displaying graphic images (e.g., pictures, slides, andsuch), text, video, audio and the like, simultaneous to the playback ofthe live media stream. In example embodiments, the command stream maycontain a sequence of commands to display text and images, such as a setof slides (e.g., PowerPoint slides). A user may load the set of slidesvia the publishing client 220 and initiate commands on the loaded set ofslides (such as sequencing to the next slide or selecting a particularslide, or displaying a slide image, a notification message, anadvertisement, a statistic, a sporting event score, a caption, atranslation, a video overlay, a question, a social media post, a chat ortext message, a survey, a live web page, a footnote, a thumbnail, achapter title, and such). The publishing server 225 receives the streamof user-initiated commands from the publishing client 220 over network340. The publishing client 220 may be logically independent of the mediaencoder 210 and streaming media server 215. The publishing server 225provisions the received stream of commands for presentation onmultimedia players 232, 234, 236. For example, the publishing server 225generates a metadata file or structure (e.g. command manifest file),such as in a text, XML, or CSV file, for the commands received from thepublishing client 220.

In embodiments of the present invention, the publishing client 220 isconfigured to the time which the media encoder 210 began encoding thelive media stream. For example, a user may enter at a user interface ofthe publishing client 220 the start time at which the media encoderbegan encoding the live media stream. In embodiments, the publishingclient 220 may also or instead be configured with an offset time thatcan be adjusted after the start time has already been configured. Forexample, a user may enter at a user interface of the publishing client220 an offset time in the case that the start time was initially enteredinaccurately, in which the offset time is the difference between theinaccurate start time and the accurate start time. FIG. 2C illustratesan example user interface for entering the offset time at the publishingclient 220 to synchronize the publishing client 220 to the media encoder210. In embodiments, the publishing client 220 may also or instead beconfigured with the location of the live media stream at the streamingmedia server 215. FIG. 2D illustrates an example user interface forentering the location of a live media stream at the streaming mediaserver 215 or elsewhere. The publishing client 220 communicates thestart time of the live media stream, the offset time, and location ofthe live media stream to the publishing server 225, where the starttime, offset time, and location may be stored in memory (cache) or topersistent storage (e.g., database). The publishing server 225 mayinclude the start time, offset time, and/or location of the live mediastream as a command (e.g., first command) appended to the commandmanifest file.

Further, when the publishing client 220 registers a user-initiatedcommand (e.g., sequencing or selecting a new slide, or displaying aslide image, a notification message, an advertisement, a statistic, asporting event score, a caption, a translation, a video overlay, aquestion, a social media post, a chat or text message, a survey, a liveweb page, a footnote, a thumbnail, and a chapter title, and such), thepublishing client 220 notifies the publishing server 225 of the command.FIG. 2E is a screenshot of an example user interface of the publishingclient that generates user-initiated commands from the user creating,updating, loading, and advancing slides (or other on-screen events) fora webcast. The publish client user interface of FIG. 2E includes a firstwindow containing a slide list 286 and features to add a slide orwebpage 283, edit speaker notes related to a slide/webpage 284, delete aslide 285, advance a slide 293, and editing a chapter title andfootnotes 294 to display for grouping slides. The publishing client userinterface also has a second window for displaying a slide preview 287,with an option to lock a previewed slide for easy editing 288. Thepublishing client user interface also includes an option to synchronize291 the publishing client 220 to the media encoder 210 (also shown inFIG. 2C), start a webcast 292 including the live media stream, get alink of the webcast to share 289, and edit program 290 information forthe webcast. A user advancing a slide 293 (or otherwise controlling thelist of slides 286) in the interface of FIG. 2E causes the publishingclient 220 to generate (register) a user-initiated command and notifiesthe publishing client 220 of the command.

The publishing client 220 may transmit in a command notification to thepublishing server 225 an identifier of the user-initiated command (e.g.,an identifier of the new sequence or selected slide of a slidepresentation), or the actual command (e.g., command type and executionparameter). The publishing client 220 may also include in thenotification the client clock time that the command was initiated or thepublishing server 225 may determine the server clock time (servertimestamp) based on the time the server received the notification. Insome embodiments, the client clock time or server clock time may be usedas the command time for executing the command. In some embodiments, thepublishing server 225 may determine the command time for the commandbased on adjusting the server clock time relative to the start time ofthe live media stream (based on the configured start time or offsetconfigured at the publishing client 220). The publishing server 225records the transmitted command together with the calculated commandtime for the command in the command manifest file. The publishing servermay also record one or more of: the current offset time to the livemedia stream, command identifier, command type, and command parameterfor executing the command in the command manifest file.

FIGS. 2F and 2G illustrate example command manifest files used inexample embodiments of the present invention. The command manifest filein FIG. 2G is the text format of the command manifest file in FIG. 2F.As shown in FIG. 2F, the command manifest file includes a list ofcommands to execute in synchronization with a corresponding live mediastream. Each command includes a server timestamp indicating the time thecommand was received at the publishing server 225 (from initiation by auser at the publishing client 220) and an offset time from the starttime of the live media stream at the media encoder 210. Each commandalso includes the command type (e.g., STAND_BY, CUEPOINT, and such) andthe parameter to execute the command. Based on polling the examplecommand manifest files of FIG. 2F, the multimedia players 232, 234, 238start broadcasting the live media stream by executing command“https://www.path.to/start_broadcasting.json” at server time1519928141000, and begin cueing the first slide in synchronization withthe live media stream at server time 1519928141000 (offset by 210000 msfrom the start time of the media encoder 210) by executing command“https://www.path.to/cuepoint_01.json”. This command is a reference to asecondary JSON cuepoint command file that in turn contains the fulldetails of the command (rather than storing the details directly in thecommand manifest file).

The following is a JSON format for a cuepoint command file in an exampleembodiment of the present invention.

{  ″time″: 0,  ″type″: ″IMAGE″,  ″source″: {   ″url″:″https://www.path.to/img/slide_01.png″,   ″properties″: [    {    ″name″: ″step″,     ″value″: ″0″    },    {     ″name″:″live-cue-index″,     ″value″: ″0″    }   ]  },  ″settings″: {  ″pause″: false,   ″zoom″: 0,   ″key″: true  },  ″metadata″: {  ″title″: ″Introduction″,   ″footnote″: ″For more information, visit     HyperNet.com″,   ″smallThumbnail″:     ″https://www.path.to/small/slide_01.jpg″,   ″largeThumbnail″:     ″https://www.path.to/large/slide_01.jpg″,   ″speakerNotes″:″Welcome to HyperNet's Human Resources      Open Enrollmentpresentation!″  } }

The multimedia players 232, 234, 238 may retrieve command stream fromthe publishing server 225, and caches the command stream. Inembodiments, the command stream may be distributed through a secondcontent distribution network (CDN) 228. The multimedia players 232, 234,238 poll the command manifest file on the publishing server 225 or CDN228 to retrieve the command type, command parameter, associated commandtime (e.g., server time), and offset time. In some embodiments, themultimedia players 232, 234, 238 also retrieve a command identifier, orretrieve the command identifier in place of the command type and commandparameter. If the sum of the media start time and the current mediaplayback time is greater than or equal to the sum of the command timeand the offset time of the command, and less than the sum of the commandtime and offset time of the next command in the stream, the multimediaplayer 232, 234, 238 executes the command, triggering an on-screen eventor visual element in the user interface (e.g., advance to a new animatedpresentation slide 280 in FIG. 2B), simultaneous to and insynchronization with the playback of the live media stream (e.g., livevideo stream 272 of FIG. 2B). The triggered on-screen event 280 displaysimultaneous to and in synchronization with the playback of the livemedia stream 272. Otherwise, the multimedia player 232, 234, 238 waitsto execute the command in the user interface of the multimedia player232, 234, 238 until the calculation of a future playback time.

Further, the multimedia players 232, 234, 238 may synchronize commandsand on-screen events to a live media stream even if the live mediastream is paused, “rewound”, “forwarded,” or otherwise adjusted in time,such as watching a digital video recorder (DVR). That is, a user mayadjust the live media stream to a new time (a different time than thecurrent playback time of the live media stream) or stop and laterre-started the live media stream (e.g., using navigation timeline 275 ofFIG. 2B). For example, the live media stream may have an availabletimeline ranging from (a) time of a first frame of the live media streamto (b) time of a current last frame of the live media stream stored atthe streaming media server 215 in a media segment referenced by themedia stream playlist. The user may select a new time anywhere on theavailable timeline to rewind, forward, or otherwise adjust and restartplayback of the live media stream (e.g., select a new time on thenavigation time 275 of FIG. 2B). For another example, the user mayinteract with a visual element (on-screen event) displayed on themultimedia player 232, 234, 238, which causes the multimedia players232, 234, 238 to re-cue/adjust the live media stream to a new selectedtime that is associated with the visual element. The multimedia players232, 234, 238 may store in memory (e.g., in a cookie) the currentplayback time prior to adjustment to the new selected time, and laterchoose an option to re-adjust playback time back to the stored currentplayback time.

The multimedia players 232, 234, 238 synchronize the on-screen events(visual elements) displayed on the interfaces of the multimedia players232, 234, 238 to the adjusted new playback time of the live mediastream. For example, if the live media stream is paused/restarted aftera delay or rewound to a point/moment in time earlier in the live mediastream, the multimedia player 232, 234, 238 synchronize the on-screenevents (visual elements) to the earlier point/moment of the live mediastream. A user may also select an on-screen event (e.g., thumbnail 276of FIG. 2B) associated with an earlier point in the live media stream,and embodiments re-cue the current playback of the live media stream tothe time of the selected visual element and synchronize the otheron-screen events (e.g., displayed slides 280 and footnotes 274 of FIG.2B) to the adjusted playback time of the live media stream.

To synchronize to the adjusted (e.g., “rewound” or paused/restarted) newtime of the live media stream, the multimedia player 232, 234, 238updates the current playback time of the live media stream to theadjusted time, and restarts the live media stream at the currentplayback time as adjusted. In some embodiments, multimedia player 232,234, 238 restarts the live media stream at a frame of a stored mediasegment at the streaming media server 215 corresponding to the new time,and presents the live media stream at the multimedia player 232, 234,238 beginning with the restarted frame corresponding to the new selectedtime. The multimedia player 232, 234, 238 then monitors the currentplayback time of the output media stream as adjusted. As part of themonitoring, the multimedia player 232, 234, 238 polls the commandmanifest file based on the current playback time as adjusted todetermine corresponding one or more commands and executes the one ormore commands to display on-screen events (visual elements) synchronizedto the current playback time of the live media stream as adjusted.

System Components for Re-Synchronizing

FIG. 3A is a block diagram of example computer components 1100 of themultimedia player 232 of FIG. 2A in embodiments of the presentinvention. FIG. 3A may also represent the computer components ofmultimedia players 234 and 238 of FIG. 2A. The multimedia player 232includes an interface 1101 configured to retrieve a live media stream ata streaming media server 215 and retrieve a command manifest file at apublishing server 225. The multimedia player 232 includes a player 1106configured to play the live media stream (received via interface 1101)and a search engine 1107 configured to locate a particular point in thelive media stream. In some embodiments, the player 1106 is a HTML5 VideoPlayer using video.js. The multimedia player 232 also includes an outputmodule 1105 configured to display the live media stream and trigger anon-screen event from a command contained in the command manifest file(received via interface 1101). The multimedia player 232 furtherincludes storage 1104 for saving (caching) some or the entire live mediastream, information from the command manifest file, and/or calculatedplayback time of the live media stream.

In addition, the multimedia player 232 includes a timing selector module1102 configured to calculate and monitor the current playback time ofthe live media stream based on the start time and time of currentlypresented frame of the live media stream. The timing selector module1102 may also adjust the current playback time of the live media streamto a user selected time (e.g., earlier point in time) of the live mediastream. The media player 232 further includes a synchronizer module 1103configured to compare the current playback time to information retrieved(via interface 1101) from the command manifest file. The retrievedinformation from the command manifest file includes user initiatedcommands and associated command times. In embodiments, the synchronizermodule 1103 is configured to compare the current playback time to thecommand times, and display an on-screen event from a command (i.e.,re-synchronize live media stream to the on-screen event) if the clocktime (e.g., server time adjusted based on offset time) is the same orgreater than the playback time.

FIG. 3B is a block diagram of computer components of the publishingclient 220 of FIG. 2A in embodiments of the present invention. Thepublishing client 220 includes an interface 1131 configured to transmitmessages to the publishing server 225 and receive input from a user. Thepublishing client 220 also includes a publisher module 136 configured toenable the user to create, update, and load media content, such asaudio, video, text, or graphic image content, and trigger a stream ofcommands on the loaded media content (such for loaded media content of aslide presentation, selecting a new slide). The publishing client 220further includes storage 1134 configured to store the media content, andoutput 1135 configured to locally display the media content to the user.

The publishing client 220 also includes a timing selector module 1132configured to set the start time of a relevant live media stream, anoffset between the start time of the live media stream and the time thatthe publishing client 220 initiates the stream of commands. The timingselector module 1132 may be further configured to transmit the set starttime and offset to the publishing server 225 (via interface 1131). Thepublishing client 220 further includes an event capturer module 1133configured to detect when a user (system or human) initiates a commandto trigger a new one-screen event of the media content. The eventcapturer module 1133 is configured to then generate and send anotification of the user-initiated command via interface 1133 to thepublishing server 225. The generated notification may include anidentifier and parameters of the command, the start time of the livemedia stream, an adjusted offset of the start time, and the location ofthe live media stream. In some embodiments, the publishing client 220may instead transmit a command time adjusted based on the set start timeof the associated media stream and the offset prior to including it inthe notification.

FIG. 3C is a block diagram of computer components of the publishingserver 225 of FIG. 2A in embodiments of the present invention. Thepublishing server 225 includes an interface 1151 configured to receivenotification of user-initiated commands and configuration parameters(e.g., command parameters, start time and offset in relation to arelevant live media stream, and location of the live media stream) frompublishing client 220, which are written to the command manifest file(e.g., FIG. 2F or FIG. 2G). The interface 1151 is also configured toreceive requests from multimedia players 232, 234, 238 for receiving thecommand manifest file containing the user-initiated commands andassociated configuration parameters. The publishing server 225 alsoincludes storage 1154 configured to store some or the entire commandmanifest file, and an output module 1155 configured to output datarelated to the user-initiated commands contained in the command manifestfile locally to a user.

The publishing client 225 also includes an event time adjuster module1152 configured to retrieve the server clock time of a newuser-initiated event contained in a received notification. The eventtime adjuster module is configured to adjust the server clock time basedon the start time of the live media stream and offset to generate acommand time. The publishing client 225 further includes an eventrecorder 1153 configured to retrieve the command identifier (includingcommand parameters) of a new triggered on-screen event contained in areceived notification. The event recorder module 1153 is configured tothen record (log) the command identifier and associated command time (orstart time, offset time, and server clock time) in the command manifestfile for the media stream.

Method of Re-Synchronizing

FIG. 4 is a flowchart of an example method 400 of re-synchronizingplayback of a live media stream with a stream of commands and on-screenevents according to embodiments of the present invention. The method 400re-synchronizes the playback of a live media stream with the executionof a stream of commands transmitted through different Internet pathways.The encoding, transmission, transcoding, distribution, download, andbuffering of the live media stream may result in a latency between thetime of capture and the time of playback in the multimedia players 232,234, 238 that is different from the latency between the time a commandwas initiated by a publisher and the time is received by the multimediaplayers. For example, a particular frame of media may be captured at themedia encoder 210 simultaneous to the time that a corresponding commandwas initiated by a publisher at the publishing client 220, but themultimedia players 232, 234, 238 may receive the command in the commandstream before the corresponding frame of media is displayed duringplayback.

The method 400 starts at step 405 by initializing encoding and streamingmedia. As part of step 405, the method 400 further captures input fromsource devices. In some embodiments, the input is at least one of videoor audio, and the source devices are at least one of: camera ormicrophone. The method 400 encodes the captured input to a standardmedia format, such as MPEG-4, H.264, and the like. The method 400transmits the encoded input as a live media stream, using a real-timestreaming protocol, to a streaming media server. The real-time streamingprotocol may be one of: Real-Time Messaging Protocol (RTMP), Real-TimeStreaming Protocol (RTSP), Web Real-Time Communications (WebRTC), andsuch.

At step 408, the method registers the start time (or zero time) of thelive media stream, which may be stored in memory (cache) or topersistent storage (e.g., database). The method 400 may also registerthe location of the live media stream and/or the offset between thestart time of the live media stream and the start time of a stream ofcommands and on-screen events may also be stored in memory (cache) or topersistent storage (e.g., database). The method may append the locationof the live media stream and the start time of the live media stream asan initial command in a command manifest file (e.g., as shown in FIGS.2F and 2G).

The live media stream may be received and provisioned at a streamingmedia server, including being divided into segments which are maintainedin an output media stream playlist, such that the playlist maintains allreferences to older media segments while gaining new referencesthroughout the full duration of the live media stream. Based on theinitial command retrieved from the command manifest file, the method400, at step 410, may continuously retrieve, cache, and present (by amultimedia player) the live media stream according to the playlist. Insome embodiments, the live media stream is a transcoded video streamthat is transmitted via HLS and played at the multimedia players by aHTML5 Video Player via a web browser in a first window or panel (asshown by 272 in FIG. 2B).

The method, at step 412, continues linear media stream playback of thelive media stream or pauses/rewinds the media stream playback of thelive media stream. For example, the user may select a new point in timeof the live media stream using the navigation timeline 275 of FIG. 2B orselect an on-screen event (e.g., thumbnail 276 of FIG. 2B) correspondingto a new point in time of the live media stream. The method 400, at step415, determines the current playback time of the live media stream. Inthe situation of consistent linear media stream playback, the determinedcurrent playback time is the time of the current last frame of the livemedia stream stored at the streaming media server (e.g., in a mediasegment referenced by the media stream playlist). In the situation wherethe media stream playback is paused/rewound, the determined currentplayback time is the selected new point in time of the live media streamtime plus the elapsed time since restarting the live media stream at theselected new point in time. In embodiments, the playback time is thenumber of milliseconds between the starting point of the media and thecurrently presented frame of the live media stream. In an exampleembodiment, the method 400 (step 415) determines the current playbacktime by polling the API of the HTML5 Video Player via the web browser.

The method also registers a stream of user-initiated commands that areappended to the end of the command manifest file (e.g., as shown inFIGS. 2F and 2G) together with a calculated command time. When themethod 400 registers a new user-initiated command (e.g., sequencing orselecting a new slide, or displaying a slide image, a notificationmessage, an advertisement, a statistic, a sporting event score, acaption, a translation, a video overlay, a question, a social mediapost, a chat or text message, a survey, a live web page, a footnote, athumbnail, a chapter title, and such) of the stream, the method 400notifies a publishing server of the new user-initiated command. Themethod may include in the notification an identifier of the newuser-initiated command (e.g., an identifier of the new sequence orselected slide of a slide presentation) or the command type andparameter. The method may also include in the notification the clocktime that the new user-initiated command was initiated or the publishingserver may determine the server clock time based on the time the serverreceived the notification. The method may determine the command time forthe registered command based on adjusting the clock time relative to theregistered start time of the live media stream or registered offset.

The method 400, at step 420, polls the command manifest file andretrieves the command identifier (and/or command type and commandparameter), associated command time (e.g., server timestamp), and offsettime of a user-initiated command (or commands) corresponding to thecurrent playback time of the live media stream. The method 400, at step425, executes the retrieved user-initiated command in the multimediaplayer based on comparison of the start time of the live media stream,current playback time (determined in step 215) to command time andoffset time. The execution triggering the on-screen event associatedwith the new user-initiated command at the multimedia player (e.g.,proceed to the new selected slide), simultaneous to and insynchronization with the playback of the live media stream 272 in awindow or panel (as shown by 280 in FIG. 2B). In some embodiments, ifthe sum of the start time and the current playback time of a particularcommand is greater than or equal to the sum of the command time and theoffset time of the command, and less than the sum of the command timeand offset time of the next command in the command stream (in commandmanifest file), the multimedia player retrieves and executes theparticular user-initiated command. Otherwise, the method 400 may wait toexecute the particular command until the calculation of a futureplayback time (if the playback time for the particular command has notalready past).

Timeline of Re-Synchronizing Media Stream to Commands

FIG. 5A is a timeline 500 of re-synchronizing the playback of a livemedia stream to a stream of commands and on-screen events in embodimentsof the present invention. The live media stream to a stream of commandsand on-screen events of the timeline are transmitted through differentInternet pathways to the multimedia player 232. The timeline 500 beginsat time 0, when a user or system enters 501 the location of the livemedia stream at the publishing client 220 of the publisher 205, which iscommunicated to the publishing server 225. At time 10, the media encoder210 starts 528 encoding the captured input from source devices to amedia format and transmitting the encoded input as a stream, using areal-time streaming protocol, to a streaming media server 215. At time15, the streaming media server 215 starts receiving and transcoding themedia stream to a live streaming format compatible with contentdelivery, and either hosts the live output media stream or transmits thelive output media stream to a Content Distribution Network (CDN) fordelivery. At time 15, the streaming media server/CON 215 starts loading504 the stream, the stream waits 505 until the multimedia player 232initializes 524 and buffers 526 the stream for playback and startsplayback 508 of the stream at time 23.

Also at time 15, a user or system enters 502 the start time of the livemedia stream and offset time from the start time for initiating streamof commands and on-screen events at the publishing client 220, which iscommunicated to the publishing server 225. The publishing server 225 mayappend the location of the live media stream and the start time of thelive media stream as an initial command in command manifest file (e.g.,as shown in FIGS. 2F and 2G). The multimedia player/viewer 232 receivesthe initial command from the command manifest file. At time 17, thepublishing server 225 executes the command in the multimedia player 232,and based on the information in the command (e.g., live media streamlocation) loads the output live media stream from the streaming mediaserver 215 or CDN and starts playback of the output live media stream.

At time 21, Command 1 is initiated 506 by a user triggering an on-screenevent at the publishing client 220, which is communicated to thepublishing server 225. The publishing server 225 appends 519 the Command1 to the command manifest file along with a server clock time forCommand 1. At time 23, the multimedia player/viewer 232 receives 520Command 1 from the command manifest file. As the sum of the live mediastream start time and the current playback time of the output live mediastream is not greater than or equal to the sum of server clock time thatCommand 1 was received, plus the offset time of Command 1, themultimedia player 232 waits until time 37 to execute 507 the Command 1for playback 522 of the associated on-screen event (re-synchronized tothe playback of the live media stream). At time 30, a user or systemadjusts the offset time 510, which is communicated to the publishingserver 225. The publishing server 225 appends the adjusted offset timeas a new command in the command manifest file.

At time 41, Command 2 is initiated 512 by a user triggering an on-screenevent at the publishing client 220, which is communicated to thepublishing server 225. The publishing server 225 appends 519 the Command2 to the command manifest file along with a server clock time forCommand 2. At time 43, the multimedia player/viewer 232 receives 520Command 2 from the command manifest file. As the sum of the live mediastream start time and the current playback time of the output live mediastream is not greater than or equal to the sum of server clock time thatCommand 1 was received, plus the adjusted offset time of Command 2, themultimedia player 232 until time 58 to execute 514 the Command 2 forplayback 522 of the associated on-screen event (re-synchronized to theplayback of the live media stream).

Similarly, at time 62, Command 3 is initiated 516 by a user triggeringan on-screen event at the publishing client 220, which is communicatedto the publishing server 225. The publishing server 225 appends theCommand 3 to the command manifest file along with a server clock timefor Command 3. At time 64, the multimedia player/viewer 232 receivesCommand 3 from the command manifest file. As the sum of the live mediastream start time and the current playback time of the output live mediastream is not greater than or equal to the sum of server clock time thatCommand 3 was received, plus the adjusted offset time of Command 3, themultimedia player 232 until time 77 to execute 518 the Command 3 forplayback 522 of the associated on-screen event (re-synchronized to theplayback of the live media stream).

Timeline of Re-Synchronizing Commands to Rewound Media Stream Time

FIG. 5B is second example of a timeline 550 of re-synchronizing theplayback of a live media stream to a stream of commands and on-screenevents in embodiments of the present invention that illustrates theDVR-style navigation capabilities of the present invention.

In this example, the timelines for the publishing client 220, publishingserver 225, media encoder 210, and streaming media server/CDN 215 remainthe same as in FIG. 5A. The difference between FIG. 5A and FIG. 5B isthat in FIG. 5B, the multimedia player 232 initializes at time 60, afterthe live media stream has been streaming from the media encoder 210 fora period of time, and several commands (Commands 1, 2, and 3) havealready been imitated/dispatched 506, 512, and 516 by the publishingclient 220. This represents the experience of a viewer who arrives lateto a live event (e.g., webcast presentation) that is already inprogress.

When the multimedia player 232 initializes and starts playback 508 attime 60, the multimedia player 232 loads the command manifest file,which at this time already includes the location of the live mediastream, as well as the first command and second command that have beendispatched/initiated 506, 512 by the publishing client 225. Themultimedia player 232 loads 504 the live stream, which now is already inprogress, and starts playing 508 from playback time 0:34. Based on thiscurrent playback time, the multimedia player 232 performs thecalculation to determine that Command 1 has already passed and insteadCommand is executed 514 immediately to accurately reflect there-synchronized state of the presentation. At time 77, the multimediaplayer 232 executes 518 Command 3, as it did in the example in FIG. 5A.At time 84, the viewer user interacts with the multimedia player andinstructs it to “rewind” 532 to playback time 0:00, which is the startof the media stream. The multimedia player 232 detects this change inplayback time and immediately resets 530 to its default initial state inwhich no commands have yet been executed. As playback continues, themultimedia player 232 now executes 507 Command 1 at time 95, andexecutes 514 Command 2 for a second time at time 115.

While example embodiments have been particularly shown and described, itwill be understood by those skilled in the art that various changes inform and details may be made therein without departing from the scope ofthe embodiments encompassed by the appended claims.

What is claimed is:
 1. A computer system for re-synchronizing playbackof a live media stream with execution of a stream of out-of-bandcommands, the system comprising: a publishing client operated by apublisher user, the publishing client configured to: obtain (i) alocation of an output media stream, (ii) a start time at which a mediaencoder began capturing and encoding an input, and (iii) an offset timeadjusting the start time at the publishing client; transmit the locationof the output media stream, the start time, and the offset time to apublishing server; enable the publisher user to initiate new commands atparticular times, the new user-initiated commands being relevant to theinput simultaneously captured and encoded by the media encoder; andtransmit the new user-initiated commands to the publishing server; thepublishing server coupled to the publishing client, the publishingserver configured to: receive the location of the output media stream,the start time, and the offset time from the publishing client; generateand maintain a command manifest file; write the received location of theoutput media stream and the start time as a first command in the commandmanifest file; receive the new user-initiated commands from thepublishing client; append the new user-initiated commands to the commandmanifest file as the user-initiated commands are received from thepublishing client, each new received user-initiated command beingappended to the end of the command manifest file, wherein each newreceived user-initiated command being appended with (i) a server clocktime indicating time the new user-initiate command is received at thepublishing server, (ii) the offset time, (iii) a command type, and (iv)a command parameter for executing the command; and at least one of: hostthe command manifest file or transmit the command manifest file to a CDNfor delivery to a multimedia player; a multimedia player running on aclient device of a viewer user, the multimedia player configured to:retrieve the command manifest file from at least one of: the publishingserver or the CDN; parse the location of the output media stream fromthe retrieved command manifest file, the parsed location being used toload and buffer the output media stream for presentation to the vieweruser; start playback of the output media stream; monitor currentplayback time of the output media stream; and determine whether toexecute a new user-initiated command to display in a user interface ofthe multimedia player by polling the command manifest file based on thecurrent playback time, if the sum of the start time and the currentplayback time is (a) greater than or equal to the sum of server clocktime of the new user-imitated command, plus the offset time of the newuser-initiated command, and (b) less than the sum of server clock timeof a next immediate new user-initiated command in the command manifestfile, plus offset time of the next immediate user-initiated command. 2.The system of claim 1, further comprising: a media encoder logicallyindependent of the publishing client and the publishing server, themedia encoder operated by the publisher user simultaneous to operationof the publishing client, the media encoder configured to: capture inputfrom source devices; encode the captured input to a media format; andtransmit the encoded input to a streaming media server as an input mediastream using a real-time streaming protocol; the streaming media servercoupled to the media encoder, the streaming media server configured to:receive the input media stream from the media encoder; transcode themedia stream to a live streaming format compatible with contentdelivery, the transcoded media stream being the output media stream, thetranscoded media stream being stored in media segments of a targetlength on the streaming media server at the location specified in thecommand manifest file; generate and maintain a media stream playlistreferencing the stored media segments; and at least one of: host theoutput media stream or transmit the output media stream to a ContentDistribution Network (CDN) for delivery to the multimedia player.
 3. Thesystem of claim 2 wherein the publishing client is configured to obtainthe start time and the offset time by at least one of: (i) prompting thepublisher user to enter the start time; (ii) prompting the publisheruser to enter the offset time; and (iii) instructing the system to enterthe start time and the offset time, the offset time captured from thestreaming media server at the time the streaming media server startsplayback of the output live media stream, the start time calculatedbased on the offset time and a time at which the streaming media serverstarts receiving and transcoding a media stream to a live streamingformat.
 4. The system of claim 2, wherein the generated media streamplaylist maintains references to older media segments of the transcodedmedia stream, while gaining references to new media segments, throughoutfull duration of the input media stream.
 5. The system of claim 2,wherein each new user-initiated command is appended to the end of thecommand manifest file as one of: a new line of text or a data object. 6.The system of claim 2, wherein the media encoder is one of: TelstraWirecast, Adobe Live Media Encoder, NewTek TriCaster, Zoom VideoWebinar, or Pexip Infinity; and the streaming media server is one of:Wowza Streaming Engine, Adobe Media Server, or a cloud-hosted SaaS/PaaSprovider, including one of: Brightcove Live Streaming Service, ZencoderLive Transcoding, Encoding.com Live Cloud Encoding, AWS ElementalMediaLive, Wowza Streaming Cloud.
 7. The system of claim 2, wherein thecaptured input is at least one of video and audio, the source devicesare at least one of: camera or microphone, and the media format is astandard format that is one of: MPEG-4 and H.264.
 8. The system of claim2, wherein the real-time streaming protocol is one of: Real-TimeMessaging Protocol (RTMP), Real-Time Streaming Protocol (RTSP), or WebReal-Time Communications (WebRTC).
 9. The system of claim 2, whereintranscoding the media streaming using a Hypertext Transfer Protocol(HTTP) protocol that is one of: HTTP Live Streaming (HLS) or MPEG-DASH.10. The system of claim 1, wherein executing the new user-initiatedcommand includes displaying on the user interface at least one of: aslide image, a notification message, an advertisement, a statistic, asporting event score, a caption, a translation, a video overlay, aquestion, a social media post, a chat or text message, a survey, a liveweb page, a footnote, a thumbnail, and a chapter title.
 11. The systemof claim 1, wherein the command manifest file is in a text format thatis one of: CSV, JSON, or XML.
 12. The system of claim 1, wherein thecurrent playback time is calculated as number of milliseconds betweenthe start time and time of a currently presented frame of the outputmedia stream.
 13. The system of claim 1, wherein the multimedia playerruns in one of: a web browser or a mobile application on the clientdevice, and the media encoder is implemented as one of a software-basedmedia encoder, a hardware-based media encoder, or a cloud-based mediaencoder.
 14. A computer-implemented method of re-synchronizing playbackof a live media stream with execution of a stream of out-of-bandcommands, the method comprising: at a publishing client operated by apublisher user: obtaining (i) a location of an output media stream, (ii)a start time at which a media encoder began capturing and encoding aninput, and (iii) an offset time adjusting the start time at thepublishing client; transmitting the location of the output media stream,the start time, and the offset time to a publishing server; enabling thepublisher user to initiate new commands at particular times, the newuser-initiated commands being relevant to the input simultaneouslycaptured and encoded by the media encoder; and transmitting the newuser-initiated commands to the publishing server; at the publishingserver coupled to the publishing client: receiving the location of theoutput media stream, the start time, and the offset time from thepublishing client; generating and maintaining a command manifest file;writing the received location of the output media stream and the starttime as a first command in the command manifest file; receiving the newuser-initiated commands from the publishing client; appending the newuser-initiated commands to the command manifest file as theuser-initiated commands are received from the publishing client, eachnew received user-initiated command being appended to the end of thecommand manifest file, wherein each new received user-initiated commandbeing appended with (i) a server clock time indicating time the newuser-initiate command is received at the publishing server, (ii) theoffset time, (iii) a command type, and (iv) a command parameter forexecuting the command; and at least one of: hosting the command manifestfile or transmitting the command manifest file to a CDN for delivery toa multimedia player; at a multimedia player running on a client deviceof a viewer user: retrieving the command manifest file from at least oneof: the publishing server or the CDN; parsing the location of the outputmedia stream from the retrieved command manifest file, the parsedlocation being used to load and buffer the output media stream forpresentation to the viewer user; starting playback of the output mediastream; monitoring current playback time of the output media stream; anddetermining whether to execute a new user-initiated command to displayin a user interface of the multimedia player by polling the commandmanifest file based on the current playback time.
 15. The method ofclaim 14 further comprising: at a media encoder logically independent ofthe publishing client and the publishing server, the media encoderoperated by the publisher user simultaneous to operation of thepublishing client: capturing input from source devices; encoding thecaptured input to a media format; and transmitting the encoded input toa streaming media server coupled to the media encoder, the encoded inputtransmitted as an input media stream using a real-time streamingprotocol; at the streaming media server: receiving the input mediastream from the media encoder; transcoding the media stream to a livestreaming format compatible with content delivery, the transcoded mediastream being the output media stream, the transcoded media stream beingstored in media segments of a target length on the streaming mediaserver at the location specified in the command manifest file;generating and maintaining a media stream playlist referencing thestored media segments; and at least one of: hosting the output mediastream or transmitting the output media stream to a Content DistributionNetwork (CDN) for delivery to the multimedia player.
 16. The method ofclaim 15 further comprising, at the publishing client, obtaining thestart time and the offset time by at least one of: (i) prompting thepublisher user to enter the start time; (ii) prompting the publisheruser to enter the offset time; and (iii) instructing the system to enterthe start time and the offset time, the offset time captured from thestreaming media server at the time the streaming media server startsplayback of the output live media stream, the start time calculatedbased on the offset time and a time at which the streaming media serverstarts receiving and transcoding a media stream to a live streamingformat.